1. Field of the Invention
The invention generally relates to electronic mail systems, and more particularly it relates to an improved method and apparatus for distribution of electronic mail.
2. The Prior Art
Electronic mail systems use unicast today to distribute mail to users on a network such as the Internet or an IP-based enterprise network. Unicast means that a unique copy of a mail message is sent to each of the destination machines.
FIG. 1 illustrates a prior art system of electronic mail distribution (100) showing the replication of mail messages in an electronic mail transmission. The electronic mail distribution system as shown in FIG. 1 comprises a plurality of client machines (102, 110a to 110x) which may be personal computers, dumb terminals, workstations, PDA's, cell phones, other terminal devices, or the equivalent. Also, the prior art electronic mail distribution system of FIG. 1 further comprises a plurality of mail servers (104, 108a to 108n) and a plurality of routers (106a to 106f).
An electronic mail message (112a . . . z) is composed on a client computer (102) with a plurality of recipients (a . . . z) that have mailboxes on machines (108a to 108n). At the client's mail server (104), the message (112a . . . z) is replicated into a plurality of messages (112a . . . z) and one copy of the message is sent to each of the destinations. Alternatively, the client computer (102) itself may replicate the message and send a copy to each of the destinations. In the Internet or in a TCP/IP based enterprise network, these copies might be sent using the well-known TCP/IP protocols.
FIG. 2 illustrates a prior art functional sequence (200) of an electronic mail distribution system. First, a mail message (112a . . . z) is created (202) at a client machine (102). Then a mail message (112a . . . z) is duplicated (204), either at a client machine (102) or at a mail server (104), for each destination (110a to 110x). Then one copy of the mail message (112a . . . z) is sent (206) to each destination mailbox on mail servers (108a to 108n).
As is well known, electronic mail uses a significant amount of bandwidth in the Internet and in enterprise networks and since mail messages are expected to increase in size as audio, image and video attachments to electronic mail become more common, electronic mail will consume even more bandwidth. This increase in the amount of bandwidth that electronic mail will consume means that either there will be less bandwidth available for other applications such as web-based applications or that more network bandwidth will be required which can be expensive. Thus, there is a need for an improved method and system for efficiently delivering electronic mail that consumes less network bandwidth.